Temperature-dependent control of flowering by the gibberellin pathwayandinteractions between DELLA proteins and APETALA1/VRN1 MADS-box factors
Temperature is an important environmental cue controlling flowering time. In Arabidopsis, the experience of cold temperatures delays growth and flowering and, at the molecular level, this growth restriction results in the accumulation of DELLA proteins, major plant growth and flowering time repressors of the gibberellin (GA) phytohormone signalling pathway. DELLA abundance responds rather instantly to changes in the temperature and the effects of DELLA accumulation can be suppressed by GA (treatments). We have previously shown that the Arabidopsis MADS-box transcription factor APETALA1 (AP1) is repressed by direct interactions with DELLAs. Furthermore, we have evidence that increased AP1 expression may be causative for the early flowering of two Arabidopsis accessions in cold temperature. Here, we would like to test the hypothesis that increased AP1 levels in these accessions outcompete the growth repressive effects of DELLAs in the cold. Second, we would like to test whether this AP1-DELLA regulatory module is conserved in cereal species. In barley and wheat, VERNALIZATION1 (VRN1) proteins, the closest homologues to Arabidopsis AP1, are major flowering time regulators. We therefore would like to examine whether barley and wheat VRN1 can also interact with the respective DELLAs and whether flowering time control in response to temperature and GA is dependent on this interaction.
Project related publications:
Lutz U,Posé D, Pfeifer M, Gundlach H, Hagmann J, Wang C, Weigel D, Mayer KFX, Schmid M, Schwechheimer C (2015). Modulation of Ambient Temperature-Dependent Flowering in Arabidopsis thaliana by Natural Variation of FLOWERING LOCUS M. PLoS Genet 11(10):e1005588. doi:10.1371/journal.pgen.1005588
Lutz U,Posé D, Pfeifer M, Gundlach H, Hagmann J, Wang C, Weigel D, Mayer KFX, Schmid M, Schwechheimer C (2015). Modulation of Ambient Temperature-Dependent Flowering in Arabidopsis thaliana by Natural Variation of FLOWERING LOCUS M. PLoS Genet 11(10):e1005588. doi:10.1371/journal.pgen.1005588Behringer C, Bastakis E, Ranftl Q, Mayer KFX, Schwechheimer C (2014). Functional diversification within the family of B-GATA transcription factors through the LLM-domain. Plant Physiology, pp.114.246660, doi: http://dx.doi.org/10.1104/pp.114.246660
Richter R, Bastakis E, Schwechheimer C (2013). Cross-repressive interactions between SOC1 and the GATAs GNC and GNL/CGA1 in the control of greening, cold tolerance and flowering time in Arabidopsis. Plant Physiology, doi:10.1104/pp.113.219238
Richter R, Behringer C, Zourelidou M, and Schwechheimer C (2013). Convergence of auxin and gibberellin signaling on the regulation of the GATA transcription factors GNC and GNL in Arabidopsis thaliana. Proceedings of the National Academy of Sciences of the United States of America, doi: 10.1073/pnas.1304250110